Revise a SPEC or EPIC PR based on review feedback and push an update. Use when a routine fires on a PR being labelled `ai:revise-now`, or when a user asks to "revise spec PR #NNN" / "revise epic PR #NNN" interactively. Non-interactive — reads every unresolved review comment + inline comment + the current SPEC/EPIC file, rewrites it, pushes to the same branch, and posts a one-line summary comment pointing at the diff.